As computer systems have become increasingly advanced the ability of the different components to communicate has become increasingly important. Correspondingly each component requires a physical medium, typical physical wires or traces, to communicate. As the number of components increases having traces between each component can quickly occupy an increased amount of space and increase cost as manufacturing complexity increases. Thus, each pin on a connector is a scarce and valuable resource.
One particular instance where the number of connections and corresponding complexity is of particular important is a backplane. A backplane typically has several connectors for connecting multiple card based components and each connector allows the various card based components to communicate with one another. For each connector, the pins of the connector are used to connect the card based components to the each other. Typically, as many of the connectors pins as possible are used for high bandwidth applications.
Correspondingly, each use of a connector pin for communication restricts the pin to use for other purposes. For example, redundancy is often required such that pins of a connector need to be used for signaling related to status and health of card based components instead for other communication between the card based components. The use of several pins on a backplane connector for the status and health information is not a particularly efficient use of scarce connector resources.
Each pin added means the connector has to be increased in size and requires additional routing increasing cost. Further, adding more routing wire may necessitate adding a layer to the backplane increasing cost and complexity. Upgrading or making a new backplane is problematic because backplane based systems currently in use would need to be disassembled to have a new backplane installed. Moreover, current card based components may not be able to operate with the increase capacity backplane connector. Thus, the inconvenience upgrading and cost of manufacturing make utilizing each pin or trace on a backplane as efficiently as possible highly desirable.